Branching of poly(ADP-ribose): Synthesis of the Core Motif

The synthesis of the core motif of branched poly­(adenosine diphosphate ribose) (poly­(ADPr)) is described, and structural analysis reasserted the proposed stereochemistry for branching. For the synthesis, a ribose trisaccharide was first constructed with only α-O-glycosidic linkages. Finally, the adenine nucleobase was introduced via a Vorbrüggen-type glycosylation reaction. The orthogonality of the selected protecting groups was demonstrated, allowing for the construction of branched poly­(ADPr) oligomers in the near future.